The present invention relates to a refrigerator, and more particularly to a refrigerator in which the evaporator or cooling unit is disposed outside, rather than inside, the refrigeration compartment.
A method and apparatus for the production of substantially purified water through the removal of impurities from raw water by a freezing process is known in the art as disclosed in, for example, Japanese Published Unexamined Patent Application No. 52-148477 filed by the present Applicant. The apparatus described in the specification of the above Application includes an ice-making unit in which ice is produced by supplying an ice-making surface with raw water circulated from a water tank for storing water used in the ice-making process, a thawing unit in which at least a portion of the manufactured ice is thawed to produce pure water, and a storage portion which stores the pure water and which allows the pure water to be taken out when necessary.
The above apparatus effects the thawing of ice by heating the ice with an electric heater or by extending the refrigeration piping of the ice-making unit to the thawing unit and supplying the latter with a hot gas through use of a compressor, thereby applying heat to the ice. However, such thawing methods inevitably consume a large quantity of electric power, either for energizing the electric heater or for driving the compressor.
A further disadvantage is encountered in the ice-making unit which circulates the raw water from the water tank and feeds the raw water to the ice-making surface to produce the ice, as described above. Specifically, residual water remains in the water tank at the conclusion of each ice-making cycle which starts with the initial supply of raw water to the ice-making surface and which ends with the formation of a prescribed quantity of ice on the ice-making surface, and this residual water must be discarded since it contains a comparatively high concentration of impurities which are concentrated during each such cycle. However, since the residual water has repeatedly passed the ice-making surface cooled by the evaporator, the temperature of the water is fairly low, i.e., on the order of almost 0.degree. C. The quantity of this residual water discarded during one ice-making cycle differs depending upon the type of pure water making apparatus, but it may be more than half, or perhaps almost equal to, the amount of ice produced by a single ice-making cycle. As this is a large quantity of water, a considerably large amount of potential heat is wastefully discarded along with the residual water.
Accordingly, it is a general object of the present invention to avoid the shortcomings encountered in the prior art as described above.
A specific object of the present invention is to provide a refrigeration apparatus which makes it possible to cool a refrigeration compartment for foods and beverages not by the direct use of an evaporator but by employing the low temperature of ice and pure water not hitherto effectively utilized in the conventional pure water-making apparatus, which refrigeration apparatus also has the capability of supplying pure water.